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Background Stromal interaction molecule (STIM)/Orai calcium entry system appears to have a role in erectile dysfunction (ED) pathophysiology but its specific contribution to diabetic ED was not elucidated. Aim To evaluate STIM/Orai inhibition on functional alterations associated with diabetic ED in rat and human penile tissues and on in vivo erectile responses in diabetic rats. Methods Rat corpus cavernosum (RCC) strips from nondiabetic (No DM) and streptozotocin-induced diabetic (DM) rats and human penile resistance arteries (HPRA) and corpus cavernosum (HCC) from ED patients undergoing penile prosthesis insertion were functionally evaluated in organ chambers and wire myographs. Erectile function in vivo in rats was assessed by intracavernosal pressure (ICP) responses to cavernous nerve electrical stimulation (CNES). Expression of STIM/Orai elements in HCC was determined by immunofluorescence and immunoblot. Main Outcome Measures Functional responses in RCC, HCC and HPRA and STIM/Orai protein expression in HCC. In vivo erectile responses to CNES. Results Inhibition of Orai channels with YM-58483 (20 µM) significantly reduced adrenergic contractions in RCC but more effectively in DM. Thromboxane-induced and neurogenic contractions were reduced by STIM/Orai inhibition while defective endothelial, neurogenic and PDE5 inhibitor-induced relaxations were enhanced by YM-58483 (10 µM) in RCC from DM rats. In vivo, YM-58483 caused erections and attenuated diabetes-related impairment of erectile responses. YM-58483 potentiated the effects of PDE5 inhibition. In human tissues, STIM/Orai inhibition depressed adrenergic and thromboxane-induced contractions in ED patients more effectively in those with type 2 diabetes. Diabetes was associated with increased expression of Orai1 and Orai3 in ED patients. Clinical Translation Targeting STIM/Orai to alleviate diabetes-related functional alterations of penile vascular tissue could improve erectile function and potentiate therapeutic effects of PDE5 inhibitors in diabetic ED. Strengths and Limitations Improving effects of STIM/Orai inhibition on diabetes-related functional impairment was evidenced in vitro and in vivo in an animal model and validated in human tissues from ED patients. Functional findings were complemented with expression results. Main limitation was low numbers of human experiments due to limited human tissue availability. Conclusions STIM/Orai inhibition alleviated alterations of functional responses in vitro and improved erectile responses in vivo in diabetic rats, potentiating the effects of PDE5 inhibition. STIM/Orai inhibition was validated as a target to modulate functional alterations of human penile vascular tissue in diabetic ED where Orai1 and Orai3 channels were upregulated. STIM/Orai inhibition could be a potential therapeutic strategy to overcome poor response to conventional ED therapy in diabetic patients.

Background Store-operated calcium entry and its key players, stromal interaction molecule (STIM) and Orai calcium channels, have been proposed as emergent therapeutic targets in cardiovascular pathophysiology. We hypothesize alteration of STIM/Orai signaling in erectile dysfunction (ED). Aim To evaluate the contribution of STIM/Orai to human penile tissue contraction and to analyze the influence of ED on STIM/Orai signaling at functional and expression levels in human penile vascular tissues. Methods Human penile resistance arteries (HPRA) and human corpus cavernosum (HCC) were dissected from cavernosal specimens from 30 organ donors without history of ED (No ED) and from 48 patients with ED undergoing penile prosthesis insertion and functionally evaluated in wire myographs and organ chambers, respectively. Expression of STIM-1, Orai1, and Orai3 in HCC was localized and quantified by immunofluorescence. Main Outcome Measures The main outcome measures are functional responses in HCC and HPRA and STIM/Orai channel protein expression in human cavernosal tissue. Results Inhibition of Orai channels with YM-58483 (20 μM) significantly reduced norepinephrine–induced contractions in both HCC and HPRA from either No ED or ED subjects, but the effects were more marked in ED (−20.1 ± 5.9% vs −45.5 ± 13.2% and −15.9 ± 4.0% vs −31.4 ± 6.9% reduction in Emax to norepinephrine in HCC and HPRA, respectively). Thromboxane-induced contractions were reduced and neurogenic contractile and relaxant responses modulated by Orai inhibition in penile tissues from patients with ED. In fact, addition of YM-58483 concentration dependently relaxed precontracted HPRA and HCC. These relaxations were significantly more pronounced in tissues from patients with ED (EC50 7.5 vs 1.3 μM and 10.5 vs 1.3 μM, for HCC and HPRA, respectively). All HCC specimens displayed expression of STIM-1, Orai1, and Orai3. Significantly increased expression of Orai1 and Orai3 but not STIM-1 was observed in patients with ED. Clinical Translation Inhibition of enhanced Orai activity in human penile vascular tissue could facilitate erectile responses, alleviating ED. Strengths and Limitations Enhanced STIM/Orai activity contribution to penile smooth muscle tone in ED is demonstrated at functional and structural levels in human tissues from a representative sample of patients with ED and in comparison with healthy tissue. We cannot differentiate the specific contribution of risk factors associated with ED to hyperactivity of the Orai system. Conclusions Orai channels significantly contribute to human penile smooth muscle contraction. Orai contribution to penile smooth muscle tone is functionally enhanced in ED accompanied by increased expression of Orai channels in cavernosal tissue. Orai inhibition could be a potential therapeutic strategy to reduce penile smooth muscle contraction in ED.

Advanced age is related to functional alterations of human vasculature, but erectile dysfunction precedes systemic manifestations of vascular disease. The current study aimed to simultaneously evaluate the influence of aging on vascular function (relaxation and contraction responses) in systemic human vascular territories: aorta (HA) and resistance mesenteric arteries (HMA) and human corpus cavernosum (HCC) and penile resistance arteries (HPRA). Associations of oxidative stress and inflammation circulating biomarkers with age and functional responses were also determined. Vascular specimens were obtained from 76 organ donors (age range 18–87). Four age-groups were established: 65 years old. Increasing age was associated with a decline in endothelium-dependent relaxation induced by BK in HMA (r = -0.597, p = 0.0001), or by ACh in HCC (r = -0.505, p = 0.0022), and HPRA (r = -0.601, p = 0.0012). Significant impairment was detected at > 65 years old in HMA but earlier in penile vasculature (> 55 years old). Age-related reduction to H(2)O(2)-vasodilatory response started before in HCC (56–65 years old) than in HA (> 65 years old). In contrast to relaxation responses, aging-related hypercontractility to adrenergic stimulation was homogeneous: contractions significantly increased in subjects > 55 years old in all tested vessels. Although not significantly age related, circulating levels of ADMA (r = -0.681, p = 0.0052) and TNF-α (r = -0.537, p = 0.0385) were negatively correlated with endothelial vasodilation in HMA but not in HCC or HPRA. Penile vasculature exhibits an early impairment of endothelium-dependent and H(2)O(2)-induced vasodilations when compared to mesenteric microcirculation and aorta. Therefore, functional susceptibility of penile vasculature to the aging process may account for anticipation of erectile dysfunction to systemic manifestations of vascular disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11357-021-00507-x.

The role of STIM/Orai calcium entry system on vascular ageing has not been elucidated. We aimed to evaluate the influence of ageing on STIM/Orai signalling and its role on ageing-induced alterations of contractile function in rat corpus cavernosum (RCC) and human penile resistance arteries (HPRA) and corpus cavernosum (HCC). RCC was obtained from 3 months-old and 20 months-old animals. HPRA and HCC were obtained from organ donors of varied ages without history of erectile dysfunction. Aging was associated with enhanced norepinephrine (NE)- and thromboxane analogue (U46619)-induced contractions in RCC which were significantly inhibited by the STIM/Orai inhibitor, YM-58483 (20 μM). Other STIM/Orai inhibitor, 2-aminoethyldiphenylborate also reduced NE-induced contractions in RCC from aged rats. YM-58483 significantly reduced neurogenic contractions and potentiated neurogenic relaxations in RCC from aged rats. In HCC and HPRA, NE-induced contractions were significantly enhanced in older subjects (>65 years-old) but YM-58483 completely reversed ageing-related hypercontractility. Ageing did not modify STIM-1 and Orai1 protein expressions but Orai3 was significantly overexpressed in cavernosal tissue from old rats and older subjects. Contribution of STIM/Orai to cavernosal contraction increases with ageing together with increased expression of Orai3. Orai inhibition could be a potential therapeutic strategy to reduce ageing-related impact on vascular/erectile function.

INTRODUCTION AND OBJECTIVE:Hydrogen sulfide (H2S) signaling has been proposed to participate in erectile physiology. L-cysteine (CYS)/H2S pathway stimulation causes cGMP-dependent relaxation of hum...

Oxidative stress contributes to endothelial dysfunction, a key step in cardiovascular disease development. Ageing-related vascular dysfunction involves defective antioxidant response. Nuclear factor erythroid 2-like-2 (Nrf2), orchestrates cellular response to oxidative stress. We evaluated the impact of Nrf2-activation on endothelium-dependent and H2O2-mediated vasodilations in: aorta (RA), mesenteric artery (RMA), coronary artery (RCA) and corpus cavernosum (RCC) from ageing rats and in human penile arteries (HPRA) and corpus cavernosum (HCC) from erectile dysfunction (ED) patients. Relaxant responses were evaluated in organ chambers and wire myographs. Nrf2 content and heme oxygenase-1 (HO-1) were determined by ELISA. Superoxide and Nrf2 were detected by immunofluorescence. Pharmacological activation of Nrf2 with sulforaphane (SFN) improved NO- and endothelium-derived hyperpolarizing factor-mediated endothelium-dependent vasodilation and H2O2-induced relaxation in vascular beds from aging rats. SFN-induced effects were associated with increased Nrf2 (RMA, RCA) and reduced superoxide detection in RCA. Improvement of vascular function was confirmed in HPRA and HCC from ED patients and mimicked by another Nrf2 activator, oltipraz. Nrf2 increase and superoxide reduction together with HO-1 increase by Nrf2 activation was evidenced in HCC from ED patients. PDE5 inhibitor-induced relaxations of HPRA and HCC from ED patients were enhanced by SFN. Nrf2 short-term pharmacological activation attenuates age-related impairment of endothelium-dependent and reactive oxygen species (ROS)-induced vasodilation in different rat and human vascular territories by upregulation of Nrf2-related signaling and decreased oxidative stress. In ED patients target tissues, Nrf2 potentiates the functional effect of ED conventional pharmacological therapy suggesting potential therapeutic implication. Keywords: Oxidative stress, Endothelial dysfunction, Nrf2, Ageing, Human vasculature, Erectile dysfunction

H2S signaling was proposed to participate in erectile physiology. L-cysteine (CYS)/H2S pathway stimulation causes cGMP-dependent relaxation of human corpus cavernosum (HCC) and penile arteries (HPRA). The aim was to evaluate the impact of ED on CYS/H2S pathway at functional and molecular level in human penile vascular tissues. NaHS- and CYS-induced responses were evaluated in HCC and HPRA from organ donors without ED (NoED, n = 29) and from ED patients undergoing penile prosthesis insertion (n = 45). cGMP accumulation and cystathionine β-synthase and cystathionine γ-lyase expression were also determined. NaHS-induced relaxations were slightly but significantly impaired in HCC but not in HPRA from ED patients. In contrast, CYS-induced relaxations were markedly impaired in HCC (Emax 67.6 ± 4.9% vs 46.2 ± 4.6%, P

INTRODUCTION AND OBJECTIVE:Renal function is highly dependent on adequate vascular function. This is especially relevant when considering the increasing use of older and marginal kidney donors to o...